Steel structures are widely used in the construction of high-rise buildings in seismic area. The strength and ductility of steel structure not only depend on its individual members but rely on the connections between these members. From past studies, however, it has been found that brittle fracture may occur at beam-to-column connections. The fracturing of connections of steel buildings in the Northridge earthquake in 1994 and Kobe earthquake in 1995 generated concerns regarding the reliability of current design and construction technology on steel connections.
In applicant's previous invention, U.S. application. Ser. No. 08/278,034, there is provided a beam-to-column connection which has tapered zones on its flange plate members. This arrangement greatly increases the ductility of the connection in a building. In this invention, the beam-to-column connection is further modified and thereby more suitable for all buildings.